Thursday, May 28, 2015

Blogging for Thor: Time & Turmeric

Hey there, Spiders! It turns out that last week's post was a bit hurried. When the red cabbage dye swatches dried completely, they revealed some very different colors as a result of the acidification tests. Acidified red cabbage dye turns blue. A rather nice blue, probably the best one I've gotten from an anthotype dye so far. You should crawl along to that post, Spiders. It's been updated with the new information and a new scan of the swatch!

Last week, I forgot to give a shout-out to Aspen's great students at UNCC. I wish I remembered which one specifically had raised the question of "what does altering the pH do to other dyes?" I knew even way back then that pH altered the color you get from red cabbage. I hadn't tested the idea on anything else. So thank you, mysterious student!

So, with all that in mind, let's take a look at the latest pH test I did: turmeric. Turmeric is one of my go-to dyes for anthotypes, but the problem with pure turmeric dye is that it's so yellow. It's almost painful to look at, and the yellow is so bright that it obscures detail and gives very little contrast. So, generally, I adulterate the turmeric with something like sandalwood or annatto to calm it down and shift it from yellow! to more of a soft yellow-orange.

The base turmeric dye is a fully saturated mixture of turmeric and isopropyl alcohol. I'm 100% sure that it's fully saturated because if left undisturbed, a full centimeter thick layer of turmeric powder precipitates to the bottom of the jar. By altering the pH of turmeric, I got the following results!

When baking soda (a base) is added to the dye, the liquid becomes a dark, garnet red. The solution dries down to orange. Again, just like the red cabbage, adding more baking soda will cause a darker, more intense color shift.

Adding vinegar (an acid) causes a similar shift, also turning the turmeric orange. This orange is a bit softer, but... again, I suspect that vinegar is diluting the dye far more than the baking soda is. That may also explain the doubled portion of vinegar causing a very soft, pale orange. That is very typical of a dilute dye.

All the adjusted dyes showed moderate dry down, becoming redder and lighter when dry, but none of them shifted as dramatically as acidic red cabbage did.

4 comments:

  1. Very interesting! I was just reading about anthotypes in an alt. photography book I have and thought that the time it takes to make a print sounded a bit long to be practical. But your examples of dye testing have some nice colors. Might be fun to try this out after I master gun bichromate.

    Good luck with the spiders!

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    1. It takes a long time to master gum bichromate. Give anthotypes a try now, while there's still plenty of sunlight! They don't take much attention since they're just sitting in a window for a week or two.

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  2. I recently started making anthotypes again and was wondering if you have any good solutions for preservation, aside from keeping them out of sunlight? I just picked up a UV protective fixative, hoping that will help.
    Thanks!

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  3. Unfortunately, no. Anthotypes will continue to fade unless protected from heat and UV light. Even the ones I've kept in an archival box and only taken out as examples in classrooms have decayed significantly over the course of two or more years. The anti-UV spray helps a tiny bit, but there's really nothing that keeps them looking new forever. It's an inherently un-archival process unless SEVERE measures are taken.

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